PDF Airport slot alleviation measures for Northern Summer 2021
The series of slots held on the HBD (Historics Baseline Date) of 23:59 UTC January 31, 2022, is used as the basis for determining eligibility for historic precedence (EC Regulation 95/93 10.3 & WASG par. 8.7.1.a).
PDF Working procedure Slot Allocation W21 - Airport Coordination Netherlands
2.1.4.Slot series returned between HBD and HBD +7 should not be reallocated to the same carrier for the same use within four weeks of HBD +7, unless there is a valid reason confirmed by the slot coordinator for reallocating these slots for use.
PDF Airport slot alleviation measures for Northern Winter 2022 (NW22) WASB ...
Slot Return Deadline and Historic Baseline Date (HBD) Until the Slot Return Deadline (SRD), which occurs about 2.5 months before the start of the season, airlines may choose to return series and slots that they do not intend to use without being penalized.